Titan Fitness Exercise Stability Ball Black 65cm Yoga Pilates Anti Burst w/Pump Active Sitting: Ergonomic support and spinal alignment. Strengthens your core as you sit. Multi-functional: Sit on it at work or home, lay down and stretch on it, or do Swiss crunches or one of many other exercises. Quality Design: The material is comfortable, durable and odor-free. Made of thick elastic PVC that will maintain its shape. Weight capacity is 300 lb. Easy to Pump & Adjust: Insert the pump to inflate. At first, ball may not measure up to stated dimensions because the elastic PVC needs to stretch, so inflate again a few days later to reach maximum size; you may want to re-inflate it occasionally. Many Benefits: Stretch on this to improve your flexibility and reduce lower back pain, improve your posture and develop core and ab strength by sitting or exercising on it.